A doctor who evaluated the girl's condition described her condition as "serial child torture," police said.

Police said they are limiting the amount of details being released about the case, but they said initial contact began on Feb. 6, when a passerby found the girl walking outside without shoes or socks. She was clad only in pajamas.

The victim was found only a couple of blocks from her house on Treichel Street and in obvious need of help, police said. A concerned citizen notified McFarland police, who in turn summoned McFarland EMS to evaluate the teen, who appeared to be malnourished. She was later transported to a Madison hospital.

On Wednesday, a hospital social worker contacted police about the girl, who weighed only 70 pounds, indicating there was more to the case and further investigation was necessary. A doctor, who specializes in child abuse, examined the teen on Friday and diagnosed her condition as "serial child torture with prolonged exposure to definite starvation," according to a police incident report.

Late on Friday, the child's 40-year-old father, Chad G. Chritton, and 42-year-old stepmother, Melinda J. Drabek-Chritton, were arrested on tentative charges of child neglect, police said. In addition, the girl's 18-year-old stepbrother, was arrested on a probation and parole hold.

The victim's father and stepmother appeared Tuesday in Dane County Circuit Court.

Prosecutors said the girl was also subjected to violence.

"Including strangulation, and (the victim) stated the primary reason she fled the house that day is it appeared this defendant was going to throw her down the stairs," said Assistant District Attorney Matt Moeser.

Chritton and Drabek-Chritton are each being held on $20,000 cash bail though they have not been formally charged. The judge told prosecutors that the suspects could be released if a criminal complaint is not filed by Thursday.

Detectives said the girl, who isn't enrolled in school, lived with her father, her stepmother, stepbrother and two younger stepchildren. While the rest of the family resided upstairs, the victim was forced to spend most of her time in the unfinished basement, without a bathroom, and being given very little to eat, police said. They said there was an alarm installed in the home if she went upstairs.

According to the probable cause affidavit, the girl was forced to urinate and defecate in the basement, and her father and stepmother "made her drink her urine as well as eat her feces."

The affidavit also said the victim "had not eaten, other than what she can pick off the floor, find in the laundry and/or take out of the garbage."

If the girl was ever caught eating without permission, she told investigators her parents made her vomit up her food, police said.

A search warrant was executed on the family's southeast Madison home on Monday, police said. They said potential evidence was seized, but investigators are continuing to conduct interviews and gather evidence.

The girl had been confined mostly to the basement since 2006, police said. The two younger stepchildren in the home are now also in protective custody.

Neighbors said the girl was rarely seen outside the home.

"(I saw her) maybe twice. She introduced herself, told me her name and her age, but in my mind she looked very young," said Bophia So, who lives next door and said she hadn't seen the girl since the summer.

The neighbor said her son sometimes played with the family's two boys, but she said neither she nor her son noticed anything amiss.

"I asked my son if there was anything suspicious in the house or if he's being mistreated or anything and he said, 'No, everything's fine. The kids were nice. The father was nice,'" Bophia So said.

The girl's stepmother helped build the home where the alleged abuse occurred as part of Habitat for Humanity in 2004, WISC-TV reported.

A Habitat for Humanity background check on Melinda Drabek -- and Chad Chritton, who was listed as an application reference -- turned up no red flags.

"Our family was a single mom and two children," said Perry Ecton, CEO of Habitat for Humanity of Dane County. "Habitat is extremely sympathetic and concerned about the child who was abused."